I love the PS1 for having a much larger library than N64. Though the N64 has some of its own unique games too. The PS1 Dual Shock is superior than the N64 controller.
I'd say PC, because Steam. I like the Dreamcast and Genesis a lot, soley for the Sonic games, sinceI am a Sonic the Hedgehog nut. There are also some other nice titles on those systems. PC wins even more because you can play the classic Sonic games and the adventure series on it.